/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.karics.library.zxing.view;

import android.annotation.SuppressLint;
import android.content.Context;
import android.content.res.Resources;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.view.View;

import com.google.zxing.ResultPoint;
import com.karics.library.zxing.camera.CameraManager;

import net.malkuth.test.R;

import java.util.ArrayList;
import java.util.List;

/**
 * This view is overlaid on top of the camera preview. It adds the viewfinder
 * rectangle and partial transparency outside it, as well as the laser scanner
 * animation and result points. 这是一个位于相机顶部的预览view,它增加了一个外部部分透明的取景框，以及激光扫描动画和结果组件
 * 
 * @author dswitkin@google.com (Daniel Switkin)
 */
public final class ViewfinderView extends View {

	private static final int[] SCANNER_ALPHA = { 0, 64, 128, 192, 255, 192,
			128, 64 };
	private static final long ANIMATION_DELAY = 80L;
	private static final int CURRENT_POINT_OPACITY = 0xA0;
	private static final int MAX_RESULT_POINTS = 20;
	private static final int POINT_SIZE = 6;

	private CameraManager cameraManager;
	private final Paint paint;
	private Bitmap resultBitmap;
	private final int maskColor; // 取景框外的背景颜色
	private final int resultColor;// result Bitmap的颜色
	private final int laserColor; // 红色扫描线的颜色
	private final int resultPointColor; // 特征点的颜色
	private final int statusColor; // 提示文字颜色
	private int scannerAlpha;
	private List<ResultPoint> possibleResultPoints;
	private List<ResultPoint> lastPossibleResultPoints;
	// 扫描线移动的y
	private int scanLineTop;
	// 扫描线移动速度
	private final int SCAN_VELOCITY = 10;
	// 扫描线
	Bitmap scanLight;

	public ViewfinderView(Context context, AttributeSet attrs) {
		super(context, attrs);

		// Initialize these once for performance rather than calling them every
		// time in onDraw().
		paint = new Paint(Paint.ANTI_ALIAS_FLAG);
		Resources resources = getResources();
		maskColor = resources.getColor(R.color.viewfinder_mask);
		resultColor = resources.getColor(R.color.result_view);
		laserColor = resources.getColor(R.color.viewfinder_laser);
		resultPointColor = resources.getColor(R.color.possible_result_points);
		statusColor = resources.getColor(R.color.green);
		scannerAlpha = 0;
		possibleResultPoints = new ArrayList<ResultPoint>(5);
		lastPossibleResultPoints = null;
		scanLight = BitmapFactory.decodeResource(resources,
				R.drawable.scan_light);
	}

	public void setCameraManager(CameraManager cameraManager) {
		this.cameraManager = cameraManager;
	}

	@SuppressLint("DrawAllocation")
	@Override
	public void onDraw(Canvas canvas) {
		if (cameraManager == null) {
			return; // not ready yet, early draw before done configuring
		}

		// frame为取景框
		Rect frame = cameraManager.getFramingRect();
		Rect previewFrame = cameraManager.getFramingRectInPreview();
		if (frame == null || previewFrame == null) {
			return;
		}
		//获取屏幕的宽和高
		int width = canvas.getWidth();
		int height = canvas.getHeight();

		paint.setColor(resultBitmap != null ? resultColor : maskColor);

		//画出扫描框外面的阴影部分，共四个部分，扫描框的上面到屏幕上面，扫描框的下面到屏幕下面
		//扫描框的左边面到屏幕左边，扫描框的右边到屏幕右边
		canvas.drawRect(0, 0, width, frame.top, paint);
		canvas.drawRect(0, frame.top, frame.left, frame.bottom + 1, paint);
		canvas.drawRect(frame.right + 1, frame.top, width, frame.bottom + 1,
				paint);
		canvas.drawRect(0, frame.bottom + 1, width, height, paint);

		if (resultBitmap != null) {
			// Draw the opaque result bitmap over the scanning rectangle
			// 如果有二维码结果的Bitmap，在扫取景框内绘制不透明的result Bitmap
			paint.setAlpha(CURRENT_POINT_OPACITY);
			canvas.drawBitmap(resultBitmap, null, frame, paint);
		} else {
			// Draw a red "laser scanner" line through the middle to show
			// decoding is active
			drawFrameBounds(canvas, frame);
			drawStatusText(canvas, frame, width);

			// 绘制扫描线
			// paint.setColor(laserColor);
			// paint.setAlpha(SCANNER_ALPHA[scannerAlpha]);
			// scannerAlpha = (scannerAlpha + 1) % SCANNER_ALPHA.length;
			// int middle = frame.height() / 2 + frame.top;
			// canvas.drawRect(frame.left + 2, middle - 1, frame.right - 1,
			// middle + 2, paint);

			drawScanLight(canvas, frame);

			float scaleX = frame.width() / (float) previewFrame.width();
			float scaleY = frame.height() / (float) previewFrame.height();

			// 绘制扫描线周围的特征点
			List<ResultPoint> currentPossible = possibleResultPoints;
			List<ResultPoint> currentLast = lastPossibleResultPoints;
			int frameLeft = frame.left;
			int frameTop = frame.top;
			if (currentPossible.isEmpty()) {
				lastPossibleResultPoints = null;
			} else {
				possibleResultPoints = new ArrayList<ResultPoint>(5);
				lastPossibleResultPoints = currentPossible;
				paint.setAlpha(CURRENT_POINT_OPACITY);
				paint.setColor(resultPointColor);
				synchronized (currentPossible) {
					for (ResultPoint point : currentPossible) {
						canvas.drawCircle(frameLeft
								+ (int) (point.getX() * scaleX), frameTop
								+ (int) (point.getY() * scaleY), POINT_SIZE,
								paint);
					}
				}
			}
			if (currentLast != null) {
				paint.setAlpha(CURRENT_POINT_OPACITY / 2);
				paint.setColor(resultPointColor);
				synchronized (currentLast) {
					float radius = POINT_SIZE / 2.0f;
					for (ResultPoint point : currentLast) {
						canvas.drawCircle(frameLeft
								+ (int) (point.getX() * scaleX), frameTop
								+ (int) (point.getY() * scaleY), radius, paint);
					}
				}
			}

			// Request another update at the animation interval, but only
			// repaint the laser line,
			// not the entire viewfinder mask.
			postInvalidateDelayed(ANIMATION_DELAY, frame.left - POINT_SIZE,
					frame.top - POINT_SIZE, frame.right + POINT_SIZE,
					frame.bottom + POINT_SIZE);
		}
	}

	/**
	 * 绘制取景框边框
	 * 
	 * @param canvas
	 * @param frame
	 */
	private void drawFrameBounds(Canvas canvas, Rect frame) {
		//设置边框颜色
		paint.setColor(Color.WHITE);
		paint.setStrokeWidth(2);
		paint.setStyle(Paint.Style.STROKE);

		canvas.drawRect(frame, paint);
		//设置边框四个角的颜色
		paint.setColor(Color.GREEN);
		paint.setStyle(Paint.Style.FILL);

		int corWidth = 15;
		int corLength = 45;

		// 左上角
		canvas.drawRect(frame.left - corWidth, frame.top, frame.left, frame.top
				+ corLength, paint);
		canvas.drawRect(frame.left - corWidth, frame.top - corWidth, frame.left
				+ corLength, frame.top, paint);
		// 右上角
		canvas.drawRect(frame.right, frame.top, frame.right + corWidth,
				frame.top + corLength, paint);
		canvas.drawRect(frame.right - corLength, frame.top - corWidth,
				frame.right + corWidth, frame.top, paint);
		// 左下角
		canvas.drawRect(frame.left - corWidth, frame.bottom - corLength,
				frame.left, frame.bottom, paint);
		canvas.drawRect(frame.left - corWidth, frame.bottom, frame.left
				+ corLength, frame.bottom + corWidth, paint);
		// 右下角
		canvas.drawRect(frame.right, frame.bottom - corLength, frame.right
				+ corWidth, frame.bottom, paint);
		canvas.drawRect(frame.right - corLength, frame.bottom, frame.right
				+ corWidth, frame.bottom + corWidth, paint);
	}

	/**
	 * 绘制提示文字
	 * 
	 * @param canvas
	 * @param frame
	 * @param width
	 */
	private void drawStatusText(Canvas canvas, Rect frame, int width) {

		String statusText1 = getResources().getString(
				R.string.viewfinderview_status_text1);
		int statusTextSize = 45;
		int statusPaddingTop = -150;

		paint.setColor(statusColor);
		paint.setTextSize(statusTextSize);
		paint.setTextSize(60);

		int textWidth1 = (int) paint.measureText(statusText1);
		canvas.drawText(statusText1, (width - textWidth1) / 2, frame.bottom - statusPaddingTop, paint);
		
	}

	/**
	 * 绘制移动扫描线
	 * 
	 * @param canvas
	 * @param frame
	 */
	private void drawScanLight(Canvas canvas, Rect frame) {

		if (scanLineTop == 0) {
			scanLineTop = frame.top;
		}

		if (scanLineTop >= frame.bottom) {
			scanLineTop = frame.top;
		} else {
			scanLineTop += SCAN_VELOCITY;
		}
		Rect scanRect = new Rect(frame.left, scanLineTop, frame.right,
				scanLineTop + 30);
		canvas.drawBitmap(scanLight, null, scanRect, paint);
	}

	public void drawViewfinder() {
		Bitmap resultBitmap = this.resultBitmap;
		this.resultBitmap = null;
		if (resultBitmap != null) {
			resultBitmap.recycle();
		}
		invalidate();
	}

	/**
	 * Draw a bitmap with the result points highlighted instead of the live
	 * scanning display.
	 * 
	 * @param barcode
	 *            An image of the decoded barcode.
	 */
	public void drawResultBitmap(Bitmap barcode) {
		resultBitmap = barcode;
		invalidate();
	}

	public void addPossibleResultPoint(ResultPoint point) {
		List<ResultPoint> points = possibleResultPoints;
		synchronized (points) {
			points.add(point);
			int size = points.size();
			if (size > MAX_RESULT_POINTS) {
				// trim it
				points.subList(0, size - MAX_RESULT_POINTS / 2).clear();
			}
		}
	}

}
